Ensure every prompt has a default response (acquia#494)

* DX-3282: Ensure every prompt has a default response

* Fixed tests

Do not show help text for invalid commands. (acquia#457)

Move help text to end of output. (acquia#453)

* Move help text to end of output.

* Rename var.

* Remove links.

* Update src/EventListener/ExceptionListener.php

Co-authored-by: Aurelien Navarre <[email protected]>

Co-authored-by: Aurelien Navarre <[email protected]>

Phar not generated for 1.7.1 (acquia#441)

Use consistent help text for environmentId. (acquia#429)

* Use consistent help text for environmentId.

* Do it for push commands.

* Move function call.

Resolve API token access issue. (acquia#419)

* Resolve API token access issue.

* Create new CloudCredentials service.

* Fix test.

* Add service everywhere.

* Fix test.

* Fix test.

* Fix test.

Update PULL_REQUEST_TEMPLATE.md

Fix Travis CI tests (curl failure) (acquia#408)

Fixes #388: ChoiceQuestion.php line 36. (acquia#390)

DX-2786: Mock SSH agent methods (acquia#378)